Not sure of the year but it is
A 2000 25elh ser#0t000097 the bottom cylinder is blown
Can this motor be bored over since the head is actually molded into the block?
Blown rimes with GONE,,,,,,,,,,you now have a parts engine. You might find a good powerhead from another engine or find another engine that needs the foot etc,
Yes, they can be bored. Done many of 'em. Pistons and rings are available from both Wiseco and Sierra in .020", .030" and .040" overbore. I've never used Sierra pistons, but the Wiseco kits come with a set of forged pistons, semi-keystone rings, new wrist pins and the retainers for the pins.
Oh, and when you rebuild your powerhead you have to get the gaskets from Mercury Marine (from a dealer). You'll need the exhaust cover/baffle gaskets, water jacket cover gasket, and lower unit mount gasket (between the powerhead and lower unit). You'll also need to order both the top and bottom crank seals and I'd automatically put new main bearings in it (the top is a 6205 and the bottom is a 6206).
The rod big end and wrist pin bearings rarely fail. Once you get the crank and recip assemblies pulled out of the cylinder block, simply side load the rods a little and rotate them around the crankpins to feel for roughness in the needle bearings. If they feel smooth don't even bother taking the rods off the crank. You can visually inspect the wrist pin bearings for brinneling.
If the engine has a lot of hours on it, have whoever does the cylinder boring dye penetrant check the reed block for unseen cracks. If it's questionable put a new one in (doesn't come with the reed petals). It'll ruin your whole day if the reed block breaks shortly after getting your engine running again, and they're prone to cracking and breaking in the thin area near the outer circumference where the reed petals seat.
Properly overhauled, and if you do the disassembly/assembly yourself, you'll spend a portion of what you can get a used motor for, and your outboard will probably run another 20 years.
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Chris
Anything can be fixed if you are a good enough experienced marine mechanic and willing to spend lots of money and time.........I saw a 25 mercury that ran well on craigslist for 500 bucks. Im sure you can fix yours for much less....lol
Anything can be fixed if you are a good enough experienced marine mechanic and willing to spend lots of money and time.........I saw a 25 mercury that ran well on craigslist for 500 bucks. Im sure you can fix yours for much less....lol
A few years back I bought a used '91 40 four-cylinder Merc that "ran well". Put it on the boat and laughed all the way to the bank, figuring I got a "good deal" on it. First walleye fishing trip it broke a reed block, a piece of the block got between the #2 rod and the crankcase and blew a hole the size of a quarter in the case.
When you overhaul something you know what you got. Buy an outboard off Craigslist and there's a better than 50% chance you're buying somebody else's problem.
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Chris
Thats how I feel about it too. I have another question about this same motor. There are two small hoses that go from below the carb tied into the reed block and they go to the inspection covers on the side of the block. One of the hoses was broke, can this cause enough problem to destroy a cylinder?
If one of those hoses is a vacuum hose it could cause a cylinder to go lean and burn it down. Without looking at the motor I don't know what hoses you're referring to offhand. But being tied to the reed block assembly I'm guessing at least one of them could be a vacuum pulse hose for the fuel pump diaphram in the side of the carb.
Since you only got one carb on a 25 and there's no apparent damage to the other cylinder, you need to look for something that would cause a vacuum leak to make that one cylinder go lean. That could be a bad crank seal, broken or unhooked vacuum hose, or even a broken or bent reed petal or broken reed block.
Teardown and inspection will probably give you a better idea of what happened.
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Chris
